The present invention generally relates to electrophotography, and more particularly, to a toner supply arrangement for supplying toner to a toner replenishing section installed in a developing unit of a copying apparatus and the like, based on an electrophotographic process.
It has been a recent trend that copying apparatuses and printers, etc. are utilized extremely frequently, and it is not seldom that forty to fifty thousand sheets of copies are taken by one unit of such an apparatus.
However, since the copying apparatuses and the like conventionally provided are generally arranged to accommodate toner in an amount only about 700 g, in the case where copying is effected in a large quantity as described above, it becomes necessary to replenish the toner frequently.
Accordingly, in an image forming apparatus for an office or the like where copying is to be effected in a large amount, it is desirable to arrange that the apparatus can accommodate as much toner as possible.
More specifically, if the apparatus is capable of accommodating toner of about 2 kg, toner is not required to be replenished for nearly one month, and it also become possible to omit work for replenishing toner at the side of a user by leaving such toner replenishing work to skilled servicing personnel.
However, due to the fact that if a large amount of toner in about 2 kg or thereabout is accommodated in one container, the toner at the bottom of the container tends to be solidified, it is required to mix and stir the toner by providing a stirring device. Moreover, since the pressure of the toner to be applied to a toner transport vane provided at the bottom portion of the container is increased, a motor with a large output is required for driving such a vane. In this case, if the above motor and motors for an optical system, a photosensitive member, and a paper transport system, etc. are driven simultaneously, power consumption will undesirably exceed an allowable value, thus making it impossible to replenish toner during formation of an image.
Furthermore, since it becomes difficult to accurately detect the remaining amount of toner when a size of the container is increased, there is a possibility that a faulty image at a low density is formed due to a delay in the toner replenishing period.